This fascinating book explains why materials behave as they do. In a completely non-technical style, using only basic arithmetic, the author explains how the properties of materials result from the way they are composed of atoms and why they have the properties they do: for example, why copper and rubies are coloured, why metals conduct heat better than glass, why magnets attract iron nails but not brass pins, and how superconductors can conduct electricity without resistance. The book is intended for general readers, and uses mainly words, pictures and analogies, with only a minimum of very simple mathematics. The author explains how it is possible to understand the basic properties of matter, and translates the technical jargon of physics into a language that can be understood by anyone with an interest in science who wants to know why the world around us behaves in the way that it does.